If 62% of the money you pay for a device is pure profit (almost**) in their pocket, then I too would expect the build quality to be nigh on perfect... this also isn't the first time that the lock screen on iOS has been the source of compromise. So yes. Shit on them from a substantial height.

(Also, I get that most people get the handset "cheap" through a contract. But those contracts are about 50 quid a month - for 24 months. That's £1164 across the contract period, leaving £544 or £22 per month for the mobile operator. So still, not exactly "cheap")